Many forms of cancer remain fatal despite advances in medical research and treatment. For example, multiple myeloma (MM) is a type of bone cancer that, despite advances in medical treatment, remains fatal.
Although there are several treatments for the disease, MM has proven difficult to acquire long-term remissions, and patients have an overall median survival of three to five years. One treatment method in current use is proteasome inhibition therapy, using, for example, Bortezomib (clinically Bortezomib, in the lab MG-132). While Bortezomib treatments have shown clinical effects on some patients diagnosed with MM, up to 12% of patients treated show no response to Bortezomib. Also, up to 30% of patients treated with Bortezomib exhibit neuropathy. Furthermore, MM has a high refractory and relapse nature and anywhere from 20% to 60% of relapsed patients who were previously treated with Bortezomib do not respond to subsequent therapies. Research has shown that some cancers, including, for example, MM, are resistant to anti-cancer effects of Bortezomib due to various mechanisms that include an increase in production of the heat shock proteins within cancer cells which can mitigate the effects of Bortezomib. Therefore, cancer cells may be initially unresponsive or eventually grow resistant to Bortezomib treatment by mechanisms that involve heat shock protein production within these cells.
Patients typically cannot be given high doses of Bortezomib in order to improve the response, as the drug is highly toxic. Also, increased dosages may induce drug resistance and/or refractiveness to treatment in cancer patients. Due to the prognosis and projected life span of current MM patients, the long-term toxicity issues to patients undergoing proteasome inhibitor treatment are a secondary concern to surviving the cancer. Thus, Bortezomib, although an excellent agent to induce some response in MM patients, lacks important properties to be used as an effective long term agent to prolong survival and achieve cure in the treatment of MM. Inadequate treatment currently exists for other types of cancer sharing one or more characteristics with MM.